The invention relates to a device for supporting a first machine part when a second machine part is subjected to force. The second machine part is mounted on the first machine part. The device supports a shaft having a tension rod, which can be displaced in the axial direction, when the tension rod is subjected to force.
In the case of rotating systems, it is generally required for a force to be introduced when at a standstill, and any contact between the rotating part and the force-introducing unit has to be avoided during the rotation. This is the case with part-changing mechanisms on rotating parts, for example in the case of spindles in automatic processing machines. In this case, the housing and the piston rod of the unit for introducing the force are conventionally arranged in a manner such that they can be displaced freely, and there is a fixed collar on the rotating machine part, against which the parts, which are provided with a gripping means, for example in the form of ratchet levers, and are connected to the cylinder housing, come to bear first and thus enclose the force flux within themselves before the force-introducing actuating force becomes effective. Solutions of this type frequently require considerable structural space.
Another solution, but one which is fairly unfavourable, is to support the forces which act outwards in the mounting of the rotating machine part without an internal frictional connection, which has a negative effect on the accuracy, the wear and the running properties.
The invention is based on the object of providing a particularly compact device for supporting a first machine when a second machine part is subjected to force.
The device according to the invention comprises a first component which can be adjusted hydraulically, pneumatically or in an electrically powered/electromagnetic manner via a threaded drive, for introducing a counterforce into the first machine part for the purpose of supporting the first machine part in a stable position, and a second component which can be adjusted powered/electromagnetic manner via a threaded drive, for subjecting the second machine part to force. The first and second components are activated at the same time and, in the manner of two cylinders acting counter to each other, equalize the internal force flux, in a manner similar to how this happens when a syringe is actuated.
In this case, the first and second components can have a piston arrangement, a diaphragm cylinder or an electromagnetic/electrically powered adjusting mechanism.
In the case of a design as a piston arrangement, the relief piston of the first component for introducing a counterforce is placed against a collar connected fixedly to the first machine part. At the same time, the relief piston comes to bear against the cylinder housing on a surface which is coordinated precisely in terms of size with the collar, which supports the counterforce of the relief piston, with the result that force is not introduced into the first machine part during support of the latter when the second machine part is subjected to force.
At the same time, in the second component a release piston, which is intended to move the second machine part in or on the first machine part, is subjected to pressure. The release piston first of all comes to bear against the second machine part and then displaces the second machine part relative to the positionally fixed first machine part. The force which is introduced via the release piston is held by the relief piston, which bears against the collar of the first machine part, with the result that the force flux is enclosed within it.
The first and second components advantageously have diaphragm cylinders, which results in a particularly short constructional length which can easily be sealed. The diaphragm cylinders can be automatically resilient or can be brought into the starting position by an additional spring arrangement.
An adjusting mechanism which can be activated in a particularly simple manner is achieved with an electromagnetic or electrically powered adjustment. This saves on structural space for hydraulic or pneumatic supply ducts, with the result that an electromagnetic/electrically powered adjustment can be used, for example, in the case of multi-stage adjusting systems.